Message-ID: <CABOYnLxH5C0y_R=cYwJYqqmNqAONRXvCEWzwtUZcQTvZt+pqfg@mail.gmail.com>
Date: Wed, 6 Mar 2024 15:12:55 +0800
From: xingwei lee <xrivendell7@...il.com>
To: Ryusuke Konishi <konishi.ryusuke@...il.com>
Cc: syzbot+47a017c46edb25eff048@...kaller.appspotmail.com, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-nilfs@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [nilfs?] KMSAN: uninit-value in nilfs_add_checksums_on_logs
 (2)

Ryusuke Konishi <konishi.ryusuke@...il.com> 于2024年3月3日周日 20:46写道：
>
> On Sun, Mar 3, 2024 at 2:46 PM xingwei lee wrote:
> >
> > Hello, I reproduced this bug.
> >
> > If you fix this issue, please add the following tag to the commit:
> > Reported-by: xingwei lee <xrivendell7@...il.com>
> >
> > Notice: I use the same config with syzbot dashboard.
> > kernel version: e326df53af0021f48a481ce9d489efda636c2dc6
> > kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
> > with KMSAN enabled
> > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> >
> > =====================================================
> > BUG: KMSAN: uninit-value in crc32_body lib/crc32.c:110 [inline]
> > BUG: KMSAN: uninit-value in crc32_le_generic lib/crc32.c:179 [inline]
> > BUG: KMSAN: uninit-value in crc32_le_base+0x475/0xe70 lib/crc32.c:197
> > crc32_body lib/crc32.c:110 [inline]
> > crc32_le_generic lib/crc32.c:179 [inline]
> > crc32_le_base+0x475/0xe70 lib/crc32.c:197
> > nilfs_segbuf_fill_in_data_crc fs/nilfs2/segbuf.c:224 [inline]
> > nilfs_add_checksums_on_logs+0xcb2/0x10a0 fs/nilfs2/segbuf.c:327
> > nilfs_segctor_do_construct+0xad1d/0xf640 fs/nilfs2/segment.c:2112
> > nilfs_segctor_construct+0x1fd/0xf30 fs/nilfs2/segment.c:2415
> > nilfs_segctor_thread_construct fs/nilfs2/segment.c:2523 [inline]
> > nilfs_segctor_thread+0x551/0x1350 fs/nilfs2/segment.c:2606
> > kthread+0x422/0x5a0 kernel/kthread.c:388
> > ret_from_fork+0x7f/0xa0 arch/x86/kernel/process.c:147
> > ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
> > Uninit was created at:
> > __alloc_pages+0x9a8/0xe00 mm/page_alloc.c:4591
> > alloc_pages_mpol+0x6b3/0xaa0 mm/mempolicy.c:2133
> > alloc_pages mm/mempolicy.c:2204 [inline]
> > folio_alloc+0x218/0x3f0 mm/mempolicy.c:2211
> > filemap_alloc_folio+0xb8/0x4b0 mm/filemap.c:974
> > __filemap_get_folio+0xa8a/0x1910 mm/filemap.c:1918
> > pagecache_get_page+0x56/0x1d0 mm/folio-compat.c:99
> > grab_cache_page_write_begin+0x61/0x80 mm/folio-compat.c:109
> > block_write_begin+0x5a/0x4a0 fs/buffer.c:2223
> > nilfs_write_begin+0x107/0x220 fs/nilfs2/inode.c:261
> > generic_perform_write+0x417/0xce0 mm/filemap.c:3927
> > __generic_file_write_iter+0x233/0x4b0 mm/filemap.c:4022
> > generic_file_write_iter+0x10e/0x600 mm/filemap.c:4048
> > __kernel_write_iter+0x365/0xa00 fs/read_write.c:523
> > dump_emit_page fs/coredump.c:888 [inline]
> > dump_user_range+0x5d7/0xe00 fs/coredump.c:915
> > elf_core_dump+0x5847/0x5fa0 fs/binfmt_elf.c:2077
> > do_coredump+0x3bb6/0x4e60 fs/coredump.c:764
> > get_signal+0x28f7/0x30b0 kernel/signal.c:2890
> > arch_do_signal_or_restart+0x5e/0xda0 arch/x86/kernel/signal.c:309
> > exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
> > exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
> > irqentry_exit_to_user_mode+0xaa/0x160 kernel/entry/common.c:225
> > irqentry_exit+0x16/0x40 kernel/entry/common.c:328
> > exc_page_fault+0x246/0x6f0 arch/x86/mm/fault.c:1566
> > asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:570
> > CPU: 1 PID: 11178 Comm: segctord Not tainted 6.7.0-00562-g9f8413c4a66f-dirty #2
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> > 1.16.2-debian-1.16.2-1 04/01/2014
> > =====================================================
> >
> > =* repro.c =*
> > #define _GNU_SOURCE
> >
> > #include <dirent.h>
> > #include <endian.h>
> > #include <errno.h>
> > #include <fcntl.h>
> > #include <sched.h>
> > #include <signal.h>
> > #include <stdarg.h>
> > #include <stdbool.h>
> > #include <stdint.h>
> > #include <stdio.h>
> > #include <stdlib.h>
> > #include <string.h>
> > #include <sys/mount.h>
> > #include <sys/prctl.h>
> > #include <sys/resource.h>
> > #include <sys/stat.h>
> > #include <sys/syscall.h>
> > #include <sys/time.h>
> > #include <sys/types.h>
> > #include <sys/wait.h>
> > #include <time.h>
> > #include <unistd.h>
> >
> > #include <linux/capability.h>
> >
> > static void sleep_ms(uint64_t ms)
> > {
> >  usleep(ms * 1000);
> > }
> >
> > static uint64_t current_time_ms(void)
> > {
> >  struct timespec ts;
> >  if (clock_gettime(CLOCK_MONOTONIC, &ts))
> >    exit(1);
> >  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
> > }
> >
> > static bool write_file(const char* file, const char* what, ...)
> > {
> >  char buf[1024];
> >  va_list args;
> >  va_start(args, what);
> >  vsnprintf(buf, sizeof(buf), what, args);
> >  va_end(args);
> >  buf[sizeof(buf) - 1] = 0;
> >  int len = strlen(buf);
> >  int fd = open(file, O_WRONLY | O_CLOEXEC);
> >  if (fd == -1)
> >    return false;
> >  if (write(fd, buf, len) != len) {
> >    int err = errno;
> >    close(fd);
> >    errno = err;
> >    return false;
> >  }
> >  close(fd);
> >  return true;
> > }
> >
> > #define MAX_FDS 30
> >
> > static void setup_common()
> > {
> >  if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
> >  }
> > }
> >
> > static void setup_binderfs()
> > {
> >  if (mkdir("/dev/binderfs", 0777)) {
> >  }
> >  if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) {
> >  }
> >  if (symlink("/dev/binderfs", "./binderfs")) {
> >  }
> > }
> >
> > static void loop();
> >
> > static void sandbox_common()
> > {
> >  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
> >  setsid();
> >  struct rlimit rlim;
> >  rlim.rlim_cur = rlim.rlim_max = (200 << 20);
> >  setrlimit(RLIMIT_AS, &rlim);
> >  rlim.rlim_cur = rlim.rlim_max = 32 << 20;
> >  setrlimit(RLIMIT_MEMLOCK, &rlim);
> >  rlim.rlim_cur = rlim.rlim_max = 136 << 20;
> >  setrlimit(RLIMIT_FSIZE, &rlim);
> >  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
> >  setrlimit(RLIMIT_STACK, &rlim);
> >  rlim.rlim_cur = rlim.rlim_max = 128 << 20;
> >  setrlimit(RLIMIT_CORE, &rlim);
> >  rlim.rlim_cur = rlim.rlim_max = 256;
> >  setrlimit(RLIMIT_NOFILE, &rlim);
> >  if (unshare(CLONE_NEWNS)) {
> >  }
> >  if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) {
> >  }
> >  if (unshare(CLONE_NEWIPC)) {
> >  }
> >  if (unshare(0x02000000)) {
> >  }
> >  if (unshare(CLONE_NEWUTS)) {
> >  }
> >  if (unshare(CLONE_SYSVSEM)) {
> >  }
> >  typedef struct {
> >    const char* name;
> >    const char* value;
> >  } sysctl_t;
> >  static const sysctl_t sysctls[] = {
> >      {"/proc/sys/kernel/shmmax", "16777216"},
> >      {"/proc/sys/kernel/shmall", "536870912"},
> >      {"/proc/sys/kernel/shmmni", "1024"},
> >      {"/proc/sys/kernel/msgmax", "8192"},
> >      {"/proc/sys/kernel/msgmni", "1024"},
> >      {"/proc/sys/kernel/msgmnb", "1024"},
> >      {"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
> >  };
> >  unsigned i;
> >  for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
> >    write_file(sysctls[i].name, sysctls[i].value);
> > }
> >
> > static int wait_for_loop(int pid)
> > {
> >  if (pid < 0)
> >    exit(1);
> >  int status = 0;
> >  while (waitpid(-1, &status, __WALL) != pid) {
> >  }
> >  return WEXITSTATUS(status);
> > }
> >
> > static void drop_caps(void)
> > {
> >  struct __user_cap_header_struct cap_hdr = {};
> >  struct __user_cap_data_struct cap_data[2] = {};
> >  cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
> >  cap_hdr.pid = getpid();
> >  if (syscall(SYS_capget, &cap_hdr, &cap_data))
> >    exit(1);
> >  const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
> >  cap_data[0].effective &= ~drop;
> >  cap_data[0].permitted &= ~drop;
> >  cap_data[0].inheritable &= ~drop;
> >  if (syscall(SYS_capset, &cap_hdr, &cap_data))
> >    exit(1);
> > }
> >
> > static int do_sandbox_none(void)
> > {
> >  if (unshare(CLONE_NEWPID)) {
> >  }
> >  int pid = fork();
> >  if (pid != 0)
> >    return wait_for_loop(pid);
> >  setup_common();
> >  sandbox_common();
> >  drop_caps();
> >  if (unshare(CLONE_NEWNET)) {
> >  }
> >  write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535");
> >  setup_binderfs();
> >  loop();
> >  exit(1);
> > }
> >
> > static void kill_and_wait(int pid, int* status)
> > {
> >  kill(-pid, SIGKILL);
> >  kill(pid, SIGKILL);
> >  for (int i = 0; i < 100; i++) {
> >    if (waitpid(-1, status, WNOHANG | __WALL) == pid)
> >      return;
> >    usleep(1000);
> >  }
> >  DIR* dir = opendir("/sys/fs/fuse/connections");
> >  if (dir) {
> >    for (;;) {
> >      struct dirent* ent = readdir(dir);
> >      if (!ent)
> >        break;
> >      if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
> >        continue;
> >      char abort[300];
> >      snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
> >               ent->d_name);
> >      int fd = open(abort, O_WRONLY);
> >      if (fd == -1) {
> >        continue;
> >      }
> >      if (write(fd, abort, 1) < 0) {
> >      }
> >      close(fd);
> >    }
> >    closedir(dir);
> >  } else {
> >  }
> >  while (waitpid(-1, status, __WALL) != pid) {
> >  }
> > }
> >
> > static void setup_test()
> > {
> >  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
> >  setpgrp();
> >  write_file("/proc/self/oom_score_adj", "1000");
> > }
> >
> > static void close_fds()
> > {
> >  for (int fd = 3; fd < MAX_FDS; fd++)
> >    close(fd);
> > }
> >
> > #define USLEEP_FORKED_CHILD (3 * 50 * 1000)
> >
> > static long handle_clone_ret(long ret)
> > {
> >  if (ret != 0) {
> >    return ret;
> >  }
> >  usleep(USLEEP_FORKED_CHILD);
> >  syscall(__NR_exit, 0);
> >  while (1) {
> >  }
> > }
> >
> > static long syz_clone(volatile long flags, volatile long stack,
> >                      volatile long stack_len, volatile long ptid,
> >                      volatile long ctid, volatile long tls)
> > {
> >  long sp = (stack + stack_len) & ~15;
> >  long ret = (long)syscall(__NR_clone, flags & ~CLONE_VM, sp, ptid, ctid, tls);
> >  return handle_clone_ret(ret);
> > }
> >
> > static void execute_one(void);
> >
> > #define WAIT_FLAGS __WALL
> >
> > static void loop(void)
> > {
> >  int iter = 0;
> >  for (;; iter++) {
> >    int pid = fork();
> >    if (pid < 0)
> >      exit(1);
> >    if (pid == 0) {
> >      setup_test();
> >      execute_one();
> >      close_fds();
> >      exit(0);
> >    }
> >    int status = 0;
> >    uint64_t start = current_time_ms();
> >    for (;;) {
> >      if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
> >        break;
> >      sleep_ms(1);
> >      if (current_time_ms() - start < 5000)
> >        continue;
> >      kill_and_wait(pid, &status);
> >      break;
> >    }
> >  }
> > }
> >
> > void execute_one(void)
> > {
> >  syz_clone(/*flags=CLONE_IO*/ 0x80000000, /*stack=*/0x20000140,
> >            /*stack_len=*/0, /*parentid=*/0, /*childtid=*/0, /*tls=*/0);
> > }
> > int main(void)
> > {
> >  syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
> >          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
> >          /*offset=*/0ul);
> >  syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul,
> >          /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul,
> >          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
> >          /*offset=*/0ul);
> >  syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
> >          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
> >          /*offset=*/0ul);
> >  do_sandbox_none();
> >  return 0;
> > }
> >
> >
> > Remember to run this repro.txt with the command: syz-execprog -repeat
> > 0 ./repro.txt and wait for about 1minus, the bug triggered very
> > steady.
> >
> > =* repro.txt =*
> > syz_mount_image$nilfs2(&(0x7f0000000000),
> > &(0x7f0000000a80)='./file0\x00', 0x808, &(0x7f00000000c0)=ANY=[], 0x1,
> > 0xa4a, &(0x7f0000001540)="$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")
> > r0 = open(&(0x7f0000000000)='./bus\x00', 0x0, 0x0) (async)
> > r1 = open(&(0x7f0000007f80)='./bus\x00', 0x145142, 0x0)
> > cachestat(r1, &(0x7f00000002c0)={0x6}, &(0x7f0000000300), 0x0) (async)
> > r2 = syz_open_procfs(0xffffffffffffffff,
> > &(0x7f0000000100)='mountinfo\x00') (async)
> > r3 = open(&(0x7f0000000a40)='./bus\x00', 0x141a42, 0x0)
> > r4 = openat$adsp1(0xffffffffffffff9c, &(0x7f0000000040), 0x20000, 0x0) (async)
> > ptrace(0x10, 0x0) (async)
> > r5 = syz_clone(0x80000000,
> > &(0x7f0000000140)="1d7f3ef3f0b0129f8d083226510ecc0713b2af6e7901a607532fa2a7176fefdd7e66e6402ef8b579a00dd83d555182afa044f65b0ac668c2063ac33b34bb48411c11d456d584ec4140aebe97e1950ad7c4bd2bffcef175625a27a11f559e8ddb031d27c2be3a2216a1e9f87f5d68b8b0b690e67bfcc8a8ec9af998c1a8eaef215c771e45eee015e8ce9b17015da79c48a7b87459c4a88781ffd9d1ec6870c4d7220ffc6a66f7828db1297aa12e00503dde7a5c",
> > 0xb3, &(0x7f0000000080), &(0x7f00000000c0),
> > &(0x7f0000000200)="994665d2b9d5239b789d65f6ec184c1ea67003ce8f474755e439f58560c42a241a31e540479e0752cad17884d9024cb854dc6798ada62550c8264b5488daff5387419b22f01fa57630317e8c24ac37d892d70e380b7164dfaa886b72a17f08df76c1057a2268b39aad4e0e759eef1abc6e5e664e7f3057c1d70d897ba5104664e96d92c1d8bd420f78368f522169f713ed03315d69de28d77af27ec8881f54633a5dd5d54635e74ad8c896918c")
> > fcntl$setown(r4, 0x8, r5) (async)
> > sendfile(r3, r2, 0x0, 0x100800001) (async)
> > sendfile(r0, r1, 0x0, 0x1000000201003)
> >
> >
> > and see also in
> > https://gist.github.com/xrivendell7/744812c87156085e12c7f617ef237875.
> > BTW, found in my personal observation, the syzlang reproducer can
> > trigger the bug more stably, so try to use the syz-execprog -repeat 0
> > ./repro.txt to trigger this bug.
> >
> > I hope it helps.
> > Best regards!
> > xingwei Lee
>
> Hi,
>
> Please let me know if you can test one.
>
> Does this issue still appear on 6.8-rc4 or later?

Hi, sorry for the delayed response.

I test my reproducer in the linux 6.8-rc4 with KMSAN kernel config for
one hours, it doesn’t trigger any crash or report as follows:

[  315.607028][   T37] audit: type=1804 audit(1709708422.469:31293):
pid=86478 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  315.608038][T86480] 884-0[86480]: segfault at 5c7ade ip
00000000005c7ade sp 00000000200001f8 error 14 likely on CPU 2 (core 2,
socke)
[  315.611270][T86480] Code: Unable to access opcode bytes at 0x5c7ab4.
[  320.575680][   T37] kauditd_printk_skb: 1253 callbacks suppressed
[  320.575689][   T37] audit: type=1804 audit(1709708427.439:32130):
pid=88573 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  320.576419][T88575] 884-0[88575]: segfault at 5c7ade ip
00000000005c7ade sp 00000000200001f8 error 14
[  320.576695][   T37] audit: type=1804 audit(1709708427.439:32131):
pid=88574 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  320.579042][T88575]  likely on CPU 0 (core 0, socket 0)
[  320.584184][T88575] Code: Unable to access opcode bytes at 0x5c7ab4.
[  320.593832][   T37] audit: type=1804 audit(1709708427.459:32132):
pid=88578 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  320.594549][T88580] 884-0[88580]: segfault at 5c7ade ip
00000000005c7ade sp 00000000200001f8 error 14 likely on CPU 1 (core 1,
socke)
[  320.596256][   T37] audit: type=1804 audit(1709708427.459:32133):
pid=88579 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  320.597901][T88580] Code: Unable to access opcode bytes at 0x5c7ab4.
[  320.610954][   T37] audit: type=1804 audit(1709708427.479:32134):
pid=88583 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  320.611700][T88585] 884-0[88585]: segfault at 5c7ade ip
00000000005c7ade sp 00000000200001f8 error 14 likely on CPU 2 (core 2,
socke)
[  320.613455][   T37] audit: type=1804 audit(1709708427.479:32135):
pid=88584 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  320.615959][T88585] Code: Unable to access opcode bytes at 0x5c7ab4.
[  320.628571][   T37] audit: type=1804 audit(1709708427.489:32136):
pid=88588 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  325.582663][   T37] kauditd_printk_skb: 1280 callbacks suppressed
[  325.582673][   T37] audit: type=1804 audit(1709708432.449:32990):
pid=90727 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  325.583320][T90729] 884-0[90729]: segfault at 5c7ade ip
00000000005c7ade sp 00000000200001f8 error 14
[  325.583460][   T37] audit: type=1804 audit(1709708432.449:32991):
pid=90728 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  325.585838][T90729]  likely on CPU 1 (core 1, socket 0)
[  325.590985][T90729] Code: Unable to access opcode bytes at 0x5c7ab4.
[  325.599620][   T37] audit: type=1804 audit(1709708432.459:32992):
pid=90732 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  325.601818][T90734] 884-0[90734]: segfault at 5c7ade ip
00000000005c7ade sp 00000000200001f8 error 14
[  325.601827][   T37] audit: type=1804 audit(1709708432.459:32993):
pid=90733 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  325.603945][T90734]  likely on CPU 2 (core 2, socket 0)
[  325.607037][T90734] Code: Unable to access opcode bytes at 0x5c7ab4.
[  325.617928][   T37] audit: type=1804 audit(1709708432.479:32994):
pid=90737 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  325.618862][T90739] 884-0[90739]: segfault at 5c7ade ip
00000000005c7ade sp 00000000200001f8 error 14
[  325.620190][   T37] audit: type=1804 audit(1709708432.479:32995):
pid=90738 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0
[  325.623238][T90739]  likely on CPU 0 (core 0, socket 0)
[  325.623803][T90739] Code: Unable to access opcode bytes at 0x5c7ab4.
[  325.632693][   T37] audit: type=1804 audit(1709708432.499:32996):
pid=90742 uid=0 auid=0 ses=1 subj=unconfined op=invalid_pcr cause=0

It’s seems this issue have been fixed.

>
> I'd like to isolate that the issue is still not fixed with the latest
> fixes, but I need to do some trial and error to reestablish a testable
> (bootable) KMSAN-enabled kernel config.
>
> Thanks,
> Ryusuke Konishi

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